Computer-assisted tele-operated surgery systems and methods

ABSTRACT

Systems and methods for minimally invasive computer-assisted telesurgery are described. For example, this disclosure provides surgical instruments and instrument drive systems for computer-assisted tele-operated surgery that are structured and operated to negate the effects of cable stretch within the surgical instruments.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/325,978 (filed on Feb. 15, 2019), which claims the benefit ofInternational Patent Application No. PCT/US2017/048425 (filed on Aug.24, 2017), which claims the benefit of priority to U.S. ProvisionalPatent Applications No. 62/379,112 (filed Aug. 24, 2016) and 62/379,114(filed Aug. 24, 2016). Each of the foregoing applications areincorporated herein by reference in their entirety.

TECHNICAL FIELD

This disclosure relates to devices and methods for minimally invasivecomputer-assisted tele-operated surgery. For example, this disclosurerelates to surgical instruments for computer-assisted tele-operatedsurgery that are structured to negate the effects of cable stretch.

BACKGROUND

Teleoperated surgical systems (often called “robotic” surgical systemsbecause of the use of robot technology) and other computer-assisteddevices often include one or more instrument manipulators to manipulateinstruments for performing a task at a surgical work site and at leastone manipulator for supporting an image capturing device which capturesimages of the surgical work site. A manipulator arm comprises aplurality of links coupled together by one or more actively controlledjoints. In many embodiments, a plurality of actively controlled jointsmay be provided. The robot arm may also include one or more passivejoints, which are not actively controlled, but which comply withmovement of an actively controlled joint. Such active and passive jointsmay be various types, including revolute or prismatic joints. Thekinematic pose of the manipulator arm and its associated instrument orimage capture device may be determined by the positions of the jointsand knowledge of the structure and coupling of the links and theapplication of known kinematic calculations.

Minimally invasive telesurgical systems for use in surgery are beingdeveloped to increase a surgeon's dexterity as well as to allow asurgeon to operate on a patient from a remote location. Telesurgery is ageneral term for surgical systems in which the surgeon uses some form ofremote control, e.g., a servomechanism, or the like, to manipulatesurgical instrument movements rather than directly holding and movingthe instruments by hand. In such a telesurgery system, the surgeon isprovided with an image of the surgical site at the remote location.While viewing typically a stereoscopic image of the surgical site thatprovides the illusion of depth on a suitable viewer or display, thesurgeon performs the surgical procedures on the patient by manipulatingmaster control input devices, which in turn control the motion ofcorresponding teleoperated instruments. The teleoperated surgicalinstruments can be inserted through small, minimally invasive surgicalapertures or natural orifices to treat tissues at surgical sites withinthe patient, often avoiding the trauma generally associated withaccessing a surgical worksite by open surgery techniques. Thesecomputer-assisted tele-operated systems can move the working ends (endeffectors) of the surgical instruments with sufficient dexterity toperform quite intricate surgical tasks, often by pivoting shafts of theinstruments at the minimally invasive aperture, sliding of the shaftaxially through the aperture, rotating of the shaft within the aperture,and the like.

SUMMARY

This disclosure provides devices and methods for minimally invasiverobotic surgery using a computer-assisted tele-operated surgery device.For example, this disclosure relates to surgical instruments forcomputer-assisted tele-operated surgery that are structured to negatethe effects of cable stretch. The devices and methods provided hereincan be used in conjunction with computer-assisted tele-operated surgerysystems (also referred to herein as “robotic surgery systems”) that useeither hardware-constrained remote centers of motion orsoftware-constrained remote centers of motion.

In one aspect, a medical device includes a surgical instrument and adrive unit for the surgical instrument. A first actuator in the driveunit is in a non-detained engagement with a first engagement member ofthe instrument, and a second actuator in the drive unit is in anon-detained engagement with a second engagement member of theinstrument. The first and second engagement members of the instrumentare coupled to the instrument's end effector, so that the end effectormoves as the first and second engagement members move. In a furtheraspect, the drive unit includes an instrument shaft actuator, theinstrument includes a shaft actuator engagement member, and theinstrument shaft actuator and the shaft actuator engagement member maybe in either a non-detained or a detained engagement.

In one aspect, a surgical instrument includes an end effector, a firstengagement member coupled to the end effector, and a second engagementmember coupled to the end effector. The first and second engagementmembers are configured to be in a non-detained engagement withcorresponding first and second actuators of a drive unit for thesurgical instrument. In a further aspect, the instrument includes ashaft actuator engagement member that is configured to be in either anon-detained or a detained engagement with a corresponding instrumentshaft actuator of the drive unit.

In one aspect, the disclosure is directed to a surgical instrument for acomputer-assisted tele-operated surgery system. The surgical instrumentincludes: a proximal end portion; an instrument shaft extending from theproximal end portion (the instrument shaft including a distal endportion opposite from the proximal end portion); an end effector coupledto the distal end portion (the end effector having at least a firstdegree of freedom whereby the end effector is movable relative to theinstrument shaft); a first tensioning member coupled to the end effectorand extending along the instrument shaft; and a second tensioning membercoupled to the end effector and extending along the instrument shaft.The second tensioning member terminates at a second actuator engagementmember. The second actuator engagement member is movably coupled to theproximal end portion. The instrument shaft defines a longitudinal axisof the surgical instrument. The first tensioning member terminates at afirst actuator engagement member. The first actuator engagement memberis movably coupled to the proximal end portion. Moving the firstactuator engagement member proximally moves the second actuatorengagement member distally and moves the end effector in a first mannerrelative to the instrument shaft. The first manner comprises movementfacilitated by the first degree of freedom. Moving the second actuatorengagement member proximally moves the first actuator engagement memberdistally and moves the end effector in a second manner relative to theinstrument shaft. The second manner is facilitated by the first degreeof freedom and opposes the first manner. The first actuator engagementmember and the second actuator engagement member are positionable at asame longitudinal location along the longitudinal axis of the surgicalinstrument.

Such a surgical instrument may optionally include one or more of thefollowing features. The proximal end portion may include a handleconfigured to facilitate manual gripping and manipulation of thesurgical instrument. The handle may extend radially from thelongitudinal axis in relation to other portions of the proximal endportion. The handle may include an RFID chip for storing informationpertaining to the surgical instrument. The handle may include anindicium identifying a type of surgical instrument. The surgicalinstrument may also include an instrument shaft actuator engagementmember coupled to the proximal end portion. The instrument shaftactuator engagement member may include a latch mechanism. The firstactuator engagement member and the second actuator engagement member mayeach be slidably coupled to the proximal end portion. The surgicalinstrument may also include one or more pre-load tensioning members thattension the first tensioning member and the second tensioning member.The one or more pre-load tensioning members may each comprise a spring.The first tensioning member and the second tensioning member may eachcomprise a cable. The end effector may have at least a second degree offreedom. The surgical instrument may also include: a third tensioningmember coupled to the end effector and extending along the instrumentshaft (the third tensioning member may terminate at a third actuatorengagement member and may be movably coupled to the proximal endportion); and a fourth tensioning member coupled to the end effector andextending along the instrument shaft (the fourth tensioning member mayterminate at a fourth actuator engagement member and may be movablycoupled to the proximal end portion). Moving the third actuatorengagement member proximally may move the fourth actuator engagementmember distally and may move the end effector in a third manner relativeto the instrument shaft (the third manner comprising movementfacilitated by the second degree of freedom). Moving the fourth actuatorengagement member proximally may move the third actuator engagementmember distally and may move the end effector in a fourth mannerrelative to the instrument shaft (the fourth manner facilitated by thesecond degree of freedom and opposing the third manner). In someembodiments, each of: (i) the first actuator engagement member, (ii) thesecond actuator engagement member, (iii) the third actuator engagementmember, and (iv) the fourth actuator engagement member are positionableat a same longitudinal location along the longitudinal axis of thesurgical instrument. The third actuator engagement member and the fourthactuator engagement member may be each slidably coupled to the proximalend portion.

In another aspect, the disclosure is directed to a surgical instrumentfor a computer-assisted tele-operated surgery system. The surgicalinstrument includes: a proximal end portion; an instrument shaftextending from the proximal end portion (the instrument shaft includes adistal end portion opposite from the proximal end portion and defines alongitudinal axis of the surgical instrument); an end effector coupledto the distal end portion (the end effector has at least a first degreeof freedom whereby the end effector is movable relative to theinstrument shaft); a first tensioning member coupled to the end effectorand extending along the instrument shaft (the first tensioning memberterminates at a first actuator engagement member that is movably coupledto the proximal end portion); a second tensioning member coupled to theend effector and extending along the instrument shaft (the secondtensioning member terminates at a second actuator engagement member thatis movably coupled to the proximal end portion); and an instrument shaftactuator engagement member that is coupled to the proximal end portion.Moving the first actuator engagement member proximally moves the secondactuator engagement member distally and moves the end effector in afirst manner relative to the instrument shaft. The first manner includesmovement facilitated by the first degree of freedom. Moving the secondactuator engagement member proximally moves the first actuatorengagement member distally and moves the end effector in a second mannerrelative to the instrument shaft. The second manner is facilitated bythe first degree of freedom and opposes the first manner. The firstactuator engagement member and the second actuator engagement member areeach configured for facilitating movements of the end effector inresponse to receiving a proximally-directed force, and are each notconfigured for facilitating movements of the end effector in response toreceiving a distally-directed force. The instrument shaft actuatorengagement member is configured for facilitating movements of the entiresurgical instrument distally in response to receiving adistally-directed force.

Such a surgical instrument may optionally include one or more of thefollowing features. The proximal end portion may include a handleconfigured to facilitate manual gripping and manipulation of thesurgical instrument. The handle may extend radially from thelongitudinal axis in relation to other portions of the proximal endportion. The handle may include an RFID chip for storing informationpertaining to the surgical instrument and an indicium identifying a typeof surgical instrument. The instrument shaft actuator engagement membermay be configured for facilitating movements of the entire surgicalinstrument proximally in response to receiving a proximally-directedforce. The instrument shaft actuator engagement member may include alatch mechanism. The first actuator engagement member and the secondactuator engagement member may be each slidably coupled to the proximalend portion and may be each positionable at a same longitudinal locationalong the longitudinal axis of the surgical instrument. The surgicalinstrument may also include one or more pre-load tensioning members thattension the first tensioning member and the second tensioning member.The one or more pre-load tensioning members may each comprise a spring.The end effector may have at least a second degree of freedom. Thesurgical instrument may also include: a third tensioning member coupledto the end effector and extending along the instrument shaft (the thirdtensioning member may terminate at a third actuator engagement memberthat may be movably coupled to the proximal end portion); and a fourthtensioning member coupled to the end effector and extending along theinstrument shaft (the fourth tensioning member may terminate at a fourthactuator engagement member that may be movably coupled to the proximalend portion). Moving the third actuator engagement member proximally maymove the fourth actuator engagement member distally and may move the endeffector in a third manner relative to the instrument shaft. The thirdmanner may include movement facilitated by the second degree of freedom.Moving the fourth actuator engagement member proximally may move thethird actuator engagement member distally and may move the end effectorin a fourth manner relative to the instrument shaft. The fourth mannermay be facilitated by the second degree of freedom and may oppose thethird manner. The third actuator engagement member and the fourthactuator engagement member may be each configured to move the endeffector in response to receiving a proximally-directed force, and maybe each configured to not move the end effector in response to receivinga distally-directed force. In some embodiments, each of: (i) the firstactuator engagement member, (ii) the second actuator engagement member,(iii) the third actuator engagement member, and (iv) the fourth actuatorengagement member may be positionable at a same longitudinal locationalong the longitudinal axis of the surgical instrument.

In another aspect, the disclosure is directed to a surgical instrumentand an instrument drive system configured to be selectively coupled withthe surgical instrument by moving the surgical instrument distally alongthe longitudinal axis into releasable engagement with the instrumentdrive system. The surgical instrument includes: a proximal end portion;an instrument shaft extending from the proximal end portion (theinstrument shaft includes a distal end portion opposite from theproximal end portion and defines a longitudinal axis of the surgicalinstrument); an end effector mounted to the distal end portion (the endeffector has at least a first degree of freedom whereby the end effectoris movable relative to the instrument shaft); a first tensioning membercoupled to the end effector and extending along the instrument shaft;and a second tensioning member coupled to the end effector and extendingalong the instrument shaft. The instrument drive system includes: afirst actuator for tensioning the first tensioning member with a firsttensile force that can move the end effector in a first manner relativeto the instrument shaft (the first manner including movement facilitatedby the first degree of freedom); a second actuator for tensioning thesecond tensioning member with a second tensile force that can move theend effector in a second manner relative to the instrument shaft (thesecond manner facilitated by the first degree of freedom and opposingthe first manner); and a shaft actuator for applying a force to theinstrument shaft (the force to the instrument shaft being directionallyopposite to the first tensile force and to the second tensile force).

Such a surgical instrument system may optionally include one or more ofthe following features. The proximal end portion may include a handleconfigured to facilitate manual gripping and manipulation of thesurgical instrument. The handle may extend radially from thelongitudinal axis and may extend farther radially than adjacent portionsof the instrument drive system while the surgical instrument is coupledwith the instrument drive system. The selective coupling of theinstrument drive system and the surgical instrument may be facilitatedby the instrument drive system slidably receiving the surgicalinstrument is moved distally along the longitudinal axis. The surgicalinstrument may also include an instrument shaft actuator engagementmember to which the shaft actuator releasably couples. The instrumentshaft actuator engagement member may include a latch mechanism. Thelatch mechanism may extend radially from the longitudinal axis and mayextend farther radially than adjacent portions of the instrument drivesystem while the surgical instrument is coupled with the instrumentdrive system. The first tensioning member may terminate at a firstactuator engagement member that is slidably coupled to the proximal endportion. The second tensioning member may terminate at a second actuatorengagement member that is slidably coupled to the proximal end portion.The first actuator may be selectively coupleable with the first actuatorengagement member. The second actuator may be selectively coupleablewith the second actuator engagement member. The first tensile force andthe second tensile force may be parallel along the instrument shaft anddirected toward the proximal end. The force to the instrument shaft maybe directed along the instrument shaft toward the distal end portion.The end effector may move in the first manner relative to the instrumentshaft when the first tensile force is greater than the second tensileforce. The end effector may move in the second manner that may be inopposition to the first manner when the second tensile force is greaterthan the first tensile force. The instrument shaft may move distally inrelation to the instrument drive system when the force to the instrumentshaft is greater than a sum of the first tensile force plus the secondtensile force. The instrument shaft may move proximally in relation tothe instrument drive system when the force to the instrument shaft isless than the sum of the first tensile force plus the second tensileforce. The end effector may have at least a second degree of freedom.The surgical instrument may also include: a third tensioning membercoupled to the end effector and extending along the instrument shaft; athird actuator for tensioning the third tensioning member with a thirdtensile force that can move the end effector in a third manner relativeto the instrument shaft (the third manner may include movementfacilitated by the second degree of freedom); a fourth tensioning membercoupled to the end effector and extending along the instrument shaft;and a fourth actuator for tensioning the fourth tensioning member with afourth tensile force that can move the end effector in a fourth mannerrelative to the instrument shaft (the fourth manner may be facilitatedby the second degree of freedom and may oppose the third manner). Theend effector may move in the third manner relative to the instrumentshaft when the third tensile force is greater than the fourth tensileforce. The end effector may move in the fourth manner that is inopposition to the third manner when the fourth tensile force is greaterthan the third tensile force. The instrument shaft may move distally inrelation to the instrument drive system when the force to the instrumentshaft is greater than a sum of the first tensile force plus the secondtensile force plus the third tensile force plus the fourth tensileforce. The instrument shaft may move proximally in relation to theinstrument drive system when the force to the instrument shaft is lessthan the sum of the first tensile force plus the second tensile forceplus the third tensile force plus the fourth tensile force. The surgicalinstrument system may also include one or more pre-load tensioningmembers that tension the first tensioning member and the secondtensioning member while the first actuator and the second actuator arenot tensioning the first tensioning member and the second tensioningmember, respectively. The one or more pre-load tensioning members mayeach comprise a spring. The surgical instrument system may also include:a first force sensor for detecting the first tensile force; a secondforce sensor for detecting the second tensile force; and an instrumentshaft force sensor for detecting the force to the instrument shaft. Eachof the first actuator, the second actuator, and the shaft actuator maybe linear actuators comprising lead screws. In some embodiments, anentirety of the surgical instrument system is configured to roll aboutthe longitudinal axis.

Some or all of the embodiments described herein may provide one or moreof the following advantages. In some cases, the tele-operated surgicalinstruments provided herein are advantageously structured to negate theeffects of cable stretch. Cables within conventional tele-operatedsurgical instruments are pre-tensioned during manufacturing, but thetensions may tend to decrease over time because the cables may stretchas the instruments are used. Such tension decreases can contribute to alessening in the accuracy of control of the tele-operated surgicalinstruments in some cases. Additionally, autoclave sterilization of thetele-operated surgical instruments using heat and humidity canexacerbate cable stretch and losses of cable tension. The tele-operatedsurgical instruments provided herein advantageously compensate for cablestretch without a loss in the accuracy of control of the instruments. Inaddition, while the tele-operated surgical instruments provided hereinare not in use, the tension on the cables is advantageously less thanthe tension during operation of the instrument. Further, thetele-operated surgical instruments provided herein advantageouslycompensate for manufacturing tolerances that pertain to cable tension.In result, the manufacturing processes of the instruments can bestreamlined and made more cost effective.

In addition, the tele-operated surgical instruments provided herein areadvantageously structured to interface with an instrument drive systemthat is compact, and has a relatively low mass and inertia. In addition,the mass distribution is substantially constant such that the inertia issubstantially constant and therefore predictable.

Still further, in some embodiments the tele-operated surgicalinstruments provided herein are advantageously structured to interfacewith an instrument drive system in a manner that is readily detachable.For example, in some embodiments the surgical instrument can be detachedfrom an instrument drive system merely by actuating a latch mechanismand retracting the instrument proximally out of engagement with thedrive system. Such a readily detachable interface between the surgicalinstrument and the instrument drive system can provide advantages suchas quick instrument removal in the event of an emergency, and userconvenience during general change-outs of one surgical instrument foranother.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example patient-side unit of acomputer-assisted tele-operated surgery system.

FIG. 2 is a front view of an example surgeon control unit of acomputer-assisted tele-operated surgery system.

FIG. 3 is a side view of an example manipulator arm assembly of acomputer-assisted tele-operated surgery system.

FIG. 4 is a perspective view of another type of patient-sidecomputer-assisted tele-operated surgery system.

FIG. 5 is a perspective view of a distal end portion of an examplesurgical instrument in a first pose.

FIG. 6 is a perspective view of the distal end portion of the surgicalinstrument of FIG. 5 in a second pose.

FIG. 7 is a perspective view of the distal end portion of the surgicalinstrument of FIG. 5 in a third pose.

FIG. 8 is a simplified schematic diagram of an example tele-operatedsurgical instrument in accordance with some embodiments.

FIG. 9 is a schematic diagram of the tele-operated surgical instrumentof FIG. 8 coupled with an example instrument drive system in accordancewith some embodiments.

FIG. 10 is a force diagram pertaining to the instrument and drive systemof FIG. 9.

FIG. 11 is a schematic diagram of the instrument and drive system ofFIG. 9 with the end effector oriented in an example pose.

FIG. 12 is a schematic diagram of the instrument and drive system ofFIG. 11 with the instrument extended distally in relation to the drivesystem while the end effector remains oriented in the example pose.

FIG. 13 is a schematic diagram of the instrument and drive system ofFIG. 11 with the instrument retracted proximally in relation to thedrive system while the end effector remains oriented in the examplepose.

FIG. 14 is a schematic diagram of a portion of the instrument and drivesystem of FIG. 11 showing example locations of force sensors fordetecting forces such as cable tension.

FIG. 15 is a perspective view of an example surgical instrument that isconfigured in accordance with the schematic diagram of FIG. 9.

FIG. 16 is a perspective view of a proximal end portion of the surgicalinstrument of FIG. 15.

FIG. 17 is another perspective view of the surgical instrument of FIG.15.

FIG. 18 is a proximal end view of the surgical instrument of FIG. 15.

FIG. 19 depicts how the surgical instrument of FIG. 15 can be coupledwith an example instrument drive system in accordance with someembodiments.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

This description and the accompanying drawings that illustrate inventiveaspects, embodiments, implementations, or applications should not betaken as limiting—the claims define the protected invention. Variousmechanical, compositional, structural, electrical, and operationalchanges may be made without departing from the spirit and scope of thisdescription and the claims. In some instances, well-known circuits,structures, or techniques have not been shown or described in detail inorder not to obscure the invention. Like numbers in two or more figuresrepresent the same or similar elements.

Further, specific words chosen to describe one or more embodiments andoptional elements or features are not intended to limit the invention.For example, spatially relative terms—such as “beneath”, “below”,“lower”, “above”, “upper”, “proximal”, “distal”, and the like—may beused to describe one element's or feature's relationship to anotherelement or feature as illustrated in the figures. These spatiallyrelative terms are intended to encompass different locations (i.e.,translational placements) and orientations (i.e., rotational placements)of a device in use or operation in addition to the location andorientation shown in the figures. For example, if a device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be “above” or “over” the other elementsor features. Thus, the exemplary term “below” can encompass bothlocations and orientations of above and below. A device may be otherwiseoriented (e.g., rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly.Likewise, descriptions of movement along (translation) and around(rotation) various axes includes various special device locations andorientations. The combination of a body's location and orientationdefine the body's pose.

Similarly, geometric terms, such as “parallel”, “perpendicular”,“round”, or “square”, are not intended to require absolute mathematicalprecision, unless the context indicates otherwise. Instead, suchgeometric terms allow for variations due to manufacturing or equivalentfunctions. For example, if an element is described as “round” or“generally round”, a component that is not precisely circular (e.g., onethat is slightly oblong or is a many-sided polygon) is still encompassedby this description. The words “including” or “having” mean includingbut not limited to.

It should be understood that although this description is made to besufficiently clear, concise, and exact, scrupulous and exhaustivelinguistic precision is not always possible or desirable, since thedescription should be kept to a reasonable length and skilled readerswill understand background and associated technology. For example,considering a video signal, a skilled reader will understand that anoscilloscope described as displaying the signal does not display thesignal itself but a representation of the signal, and that a videomonitor described as displaying the signal does not display the signalitself but video information the signal carries.

In addition, the singular forms “a”, “an”, and “the” are intended toinclude the plural forms as well, unless the context indicatesotherwise. And, the terms “comprises”, “includes”, “has”, and the likespecify the presence of stated features, steps, operations, elements,and/or components but do not preclude the presence or addition of one ormore other features, steps, operations, elements, components, and/orgroups. And, each of the one or more individual listed items should beconsidered optional unless otherwise stated, so that variouscombinations of items are described without an exhaustive list of eachpossible combination. The auxiliary verb may likewise implies that afeature, step, operation, element, or component is optional.

Elements described in detail with reference to one embodiment,implementation, or application optionally may be included, wheneverpractical, in other embodiments, implementations, or applications inwhich they are not specifically shown or described. For example, if anelement is described in detail with reference to one embodiment and isnot described with reference to a second embodiment, the element maynevertheless be claimed as included in the second embodiment. Thus, toavoid unnecessary repetition in the following description, one or moreelements shown and described in association with one embodiment,implementation, or application may be incorporated into otherembodiments, implementations, or aspects unless specifically describedotherwise, unless the one or more elements would make an embodiment orimplementation non-functional, or unless two or more of the elementsprovide conflicting functions.

Elements described as coupled may be electrically or mechanicallydirectly coupled, or they may be indirectly coupled via one or moreintermediate components.

The term “flexible” in association with a part, such as a mechanicalstructure, component, or component assembly, should be broadlyconstrued. In essence, the term means the part can be repeatedly bentand restored to an original shape without harm to the part. Many “rigid”objects have a slight inherent resilient “bendiness” due to materialproperties, although such objects are not considered “flexible” as theterm is used herein. A flexible part may have infinite degrees offreedom (DOF's). Examples of such parts include closed, bendable tubes(made from, e.g., NITINOL, polymer, soft rubber, and the like), helicalcoil springs, etc. that can be bent into various simple or compoundcurves, often without significant cross-sectional deformation. Otherflexible parts may approximate such an infinite-DOF part by using aseries of closely spaced components that are similar to a snake-likearrangement of serial “vertebrae.” In such a vertebral arrangement, eachcomponent is a short link in a kinematic chain, and movable mechanicalconstraints (e.g., pin hinge, cup and ball, live hinge, and the like)between each link may allow one (e.g., pitch) or two (e.g., pitch andyaw) DOF's of relative movement between the links. A short, flexiblepart may serve as, and be modeled as, a single mechanical constraint(joint) that provides one or more DOF's between two links in a kinematicchain, even though the flexible part itself may be a kinematic chainmade of several coupled links. Knowledgeable persons will understandthat a part's flexibility may be expressed in terms of its stiffness.

Unless otherwise stated in this description, a flexible part, such as amechanical structure, component, or component assembly, may be eitheractively or passively flexible. An actively flexible part may be bent byusing forces inherently associated with the part itself. For example,one or more tendons may be routed lengthwise along the part and offsetfrom the part's longitudinal axis, so that tension on the one or moretendons causes the part or a portion of the part to bend. Other ways ofactively bending an actively flexible part include, without limitation,the use of pneumatic or hydraulic power, gears, electroactive polymer(more generally, “artificial muscle”), and the like. A passivelyflexible part is bent by using a force external to the part (e.g., anapplied mechanical or electromagnetic force). A passively flexible partmay remain in its bent shape until bent again, or it may have aninherent characteristic that tends to restore the part to an originalshape. An example of a passively flexible part with inherent stiffnessis a plastic rod or a resilient rubber tube. An actively flexible part,when not actuated by its inherently associated forces, may be passivelyflexible. A single part may be made of one or more actively andpassively flexible parts in series.

An example of a teleoperated surgical system is the da Vinci® SurgicalSystem, commercialized by Intuitive Surgical, Inc. of Sunnyvale, Calif.Inventive aspects are associated with computer-assisted teleoperatedsurgical systems. Knowledgeable persons will understand that inventiveaspects disclosed herein may be embodied and implemented in variousways, including computer-assisted and hybrid combinations of manual andcomputer-assisted embodiments and implementations. As applicable,inventive aspects may be embodied and implemented in both relativelysmaller, hand-held, hand-operated devices and relatively larger systemsthat have additional mechanical support, as well as in other embodimentsof computer-assisted tele-operated medical devices. In addition,inventive aspects are associated with advances in computer-assistedsurgical systems that include autonomous rather than teleoperatedactions, and so both teleoperated and autonomous surgical systems areincluded, even though the description concentrates on teleoperatedsystems.

A computer is a machine that follows programmed instructions to performmathematical or logical functions on input information to produceprocessed output information. A computer includes a logic unit thatperforms the mathematical or logical functions, and memory that storesthe programmed instructions, the input information, and the outputinformation. The term “computer” and similar terms, such as “processor”or “controller”, encompasses both centralized single-location anddistributed implementations.

This disclosure provides improved surgical and telesurgical devices,systems, and methods. The inventive concepts are particularlyadvantageous for use with telesurgical systems in which a plurality ofsurgical tools or instruments are mounted on and moved by an associatedplurality of teleoperated manipulators during a surgical procedure. Theteleoperated surgical systems will often comprise tele-robotic,telesurgical, and/or telepresence systems that include processorsconfigured as master-slave controllers. By providing teleoperatedsurgical systems employing processors appropriately configured to movemanipulator assemblies with articulated linkages having relatively largenumbers of degrees of freedom, the motion of the linkages can betailored for work through a minimally invasive access site. The largenumber of degrees of freedom may also allow a processor to position themanipulators to inhibit interference or collisions between these movingstructures, and the like.

The manipulator assemblies described herein will often include ateleoperated manipulator and a tool mounted thereon (the tool oftencomprising a surgical instrument in surgical versions), although theterm “manipulator assembly” will also encompass the manipulator withoutthe tool mounted thereon. The term “tool” encompasses both general orindustrial robotic tools and specialized robotic surgical instruments,with these later structures often including an end effector that issuitable for manipulation of tissue, treatment of tissue, imaging oftissue, or the like. The tool/manipulator interface will often be aquick disconnect tool holder or coupling, allowing rapid removal andreplacement of the tool with an alternate tool. The manipulator assemblywill often have a base that is fixed in space during at least a portionof a telesurgical procedure, and the manipulator assembly may include anumber of degrees of freedom between the base and an end effector of thetool. Actuation of the end effector (such as opening or closing of thejaws of a gripping device, energizing an electrosurgical paddle, or thelike) will often be separate from, and in addition to, these manipulatorassembly degrees of freedom.

The end effector will typically move in the workspace with between twoand six degrees of freedom. As used herein, the term “position”encompasses both location and orientation. Hence, a change in a positionof an end effector (for example) may involve a translation of the endeffector from a first location to a second location, a rotation of theend effector from a first orientation to a second orientation, or acombination of both. As used herein, the term “end effector” thereforeincludes but is not limited to the function of changing the orientationor position (e.g., a “wrist” function, a parallel motion function) ofits distal-most part or parts (e.g., jaw(s) and the like).

When used for minimally invasive teleoperated surgery, movement of themanipulator assembly may be controlled by a processor of the system sothat a shaft or intermediate portion of the tool or instrument isconstrained to a safe motion through a minimally invasive surgicalaccess site or other aperture. Such motion may include, for example,axial insertion of the shaft through the aperture site, rotation of theshaft about its axis, and pivotal motion of the shaft about a pivotpoint adjacent the access site, but will often preclude excessivelateral motion of the shaft which might otherwise tear the tissuesadjacent the aperture or enlarge the access site inadvertently. Some orall of such constraint on the manipulator motion at the access site maybe imposed using mechanical manipulator joint linkages that inhibitimproper motions, or may in part or in full be imposed using roboticdata processing and control techniques. Hence, such minimally invasiveaperture-constrained motion of the manipulator assembly may employbetween zero and three degrees of freedom of the manipulator assembly.

Many of the exemplary manipulator assemblies described herein will havemore degrees of freedom than are needed to position and move an endeffector within a surgical site. For example, a surgical end effectorthat can be positioned with six degrees of freedom at an internalsurgical site through a minimally invasive aperture may in someembodiments have nine degrees of freedom (six end effector degrees offreedom—three for location, and three for orientation—plus three degreesof freedom to comply with the access site constraints), but will oftenhave ten or more degrees of freedom. Highly configurable manipulatorassemblies having more degrees of freedom than are needed for a givenend effector position can be described as having or providing sufficientdegrees of freedom to allow a range of joint states for an end effectorposition in a workspace. For example, for a given end effector position,the manipulator assembly may occupy (and be driven between) any of arange of alternative manipulator linkage positions. Similarly, for agiven end effector velocity vector, the manipulator assembly may have arange of differing joint movement speeds for the various joints of themanipulator assembly.

Referring to FIGS. 1 and 2, systems for minimally invasivecomputer-assisted telesurgery (as referred to herein as “minimallyinvasive robotic surgery”) can include a patient-side unit 100 and asurgeon control unit 40. Telesurgery is a general term for surgicalsystems where the surgeon uses some form of remote control, e.g., aservomechanism, or the like, to manipulate surgical instrument movementsby using robot technology rather than directly holding and moving theinstruments by hand. The robotically manipulatable surgical instrumentscan be inserted through small, minimally invasive surgical apertures totreat tissues at surgical sites within the patient, avoiding the traumaassociated with accessing for open surgery. These robotic systems canmove the working ends of the surgical instruments with sufficientdexterity to perform quite intricate surgical tasks, often by pivotingshafts of the instruments at the minimally invasive aperture, sliding ofthe shaft axially through the aperture, rotating of the shaft within theaperture, and/or the like.

In the depicted embodiment, the patient-side unit 100 includes a base110, a first robotic manipulator arm assembly 120, a second roboticmanipulator arm assembly 130, a third robotic manipulator arm assembly140, and a fourth robotic manipulator arm assembly 150. As shown, thebase 110 includes a portion that rests on the floor, a vertical column,and a horizontal boom, and other base configurations to mechanicallyground the patient-side unit may optionally be used. Each roboticmanipulator arm assembly 120, 130, 140, and 150 is pivotably coupled tothe base 110. In some embodiments, fewer than four or more than fourrobotic manipulator arm assemblies may be included as part of thepatient-side unit100. While in the depicted embodiment the base 110includes casters to allow ease of mobility, in some embodiments thepatient-side unit100 is fixedly mounted to a floor, ceiling, operatingtable, structural framework, or the like.

In a typical application, two of the robotic manipulator arm assemblies120, 130, 140, or 150 hold surgical instruments and a third holds astereo endoscope. The remaining robotic manipulator arm assembly isavailable so that another instrument may be introduced at the work site.Alternatively, the remaining robotic manipulator arm assembly may beused for introducing a second endoscope or another image capturingdevice, such as an ultrasound transducer, to the work site.

Each of the robotic manipulator arm assemblies 120, 130, 140, and 150 isconventionally formed of links that are coupled together and manipulatedthrough actuatable joints. Each of the robotic manipulator armassemblies 120, 130, 140, and 150 includes a setup arm and a devicemanipulator. The setup arm positions its held device so that a pivotpoint occurs at its entry aperture into the patient. The devicemanipulator may then manipulate its held device (tool; surgicalinstrument) so that it may be pivoted about the pivot point, insertedinto and retracted out of the entry aperture, and rotated about itsshaft axis.

In the depicted embodiment, the surgeon console 40 includes a stereovision display 45 so that the user may view the surgical work site instereo vision from images captured by the stereoscopic camera of thepatient-side cart 100. Left and right eyepieces 46 and 47 are providedin the stereo vision display 45 so that the user may view left and rightdisplay screens inside the display 45 respectively with the user's leftand right eyes. While viewing typically an image of the surgical site ona suitable viewer or display, the surgeon performs the surgicalprocedures on the patient by manipulating master control input devices,which in turn control the motion of robotic instruments.

The surgeon console 40 also includes left and right input devices 41, 42that the user may grasp respectively with his/her left and right handsto manipulate devices (e.g., surgical instruments) being held by therobotic manipulator arm assemblies 120, 130, 140, and 150 of thepatient-side cart 100 in preferably six degrees-of-freedom (“DOF”). Footpedals 44 with toe and heel controls are provided on the surgeon console40 so the user may control movement and/or actuation of devicesassociated with the foot pedals. Additional input to the system may bemade via one or more other inputs, such as buttons, touch pads, voice,and the like, as illustrated by input 49.

A processor 43 is provided in the surgeon console 40 for control andother purposes. The processor 43 performs various functions in themedical robotic system. One function performed by processor 43 is totranslate and transfer the mechanical motion of input devices 41, 42 toactuate their respective joints in their associated robotic manipulatorarm assemblies 120, 130, 140, and 150 so that the surgeon caneffectively manipulate devices, such as the surgical instruments.Another function of the processor 43 is to implement the methods,cross-coupling control logic, and controllers described herein.

Although described as a processor, it is to be appreciated that theprocessor 43 may be implemented by any combination of hardware,software, and firmware. Also, its functions as described herein may beperformed by one unit or divided up among a number of subunits, each ofwhich may be implemented in turn by any combination of hardware,software, and firmware. Further, although being shown as part of orbeing physically adjacent to the surgeon control unit 40, the processor43 may also be distributed as subunits throughout the telesurgerysystem. Accordingly, control aspects referred to herein are implementedvia processor 43 in either a centralized or distributed form.

Referring also to FIG. 3, the robotic manipulator arm assemblies 120,130, 140, and 150 can manipulate devices such as surgical instruments toperform minimally invasive surgery. For example, in the depictedarrangement the robotic manipulator arm assembly 120 is pivotablycoupled to an instrument holder 122. A cannula 180 and a surgicalinstrument 200 and are, in turn, releasably coupled to the instrumentholder 122. The cannula 180 is a tubular member that is located at thepatient interface site during a surgery. The cannula 180 defines a lumenin which an elongate shaft 220 of the surgical instrument 200 isslidably disposed. As described further below, in some embodiments thecannula 180 includes a distal end portion with a body wall retractormember.

The instrument holder 122 is pivotably coupled to a distal end of therobotic manipulator arm assembly 120. In some embodiments, the pivotablecoupling between the instrument holder 122 and the distal end of roboticmanipulator arm assembly 120 is a motorized joint that is actuatablefrom the surgeon console 40 and processor 43.

The instrument holder 122 includes an instrument holder frame 124, acannula clamp 126, and an instrument holder carriage 128. In thedepicted embodiment, the cannula clamp 126 is fixed to a distal end ofthe instrument holder frame 124. The cannula clamp 126 can be actuatedto couple with, or to uncouple from, the cannula 180. The instrumentholder carriage 128 is movably coupled to the instrument holder frame124. More particularly, the instrument holder carriage 128 is linearlytranslatable along the instrument holder frame 124. In some embodiments,the movement of the instrument holder carriage 128 along the instrumentholder frame 124 is a motorized, translational movement that isactuatable/controllable by the processor 43.

The surgical instrument 200 includes a transmission assembly 210, theelongate shaft 220, and an end effector 230. The transmission assembly210 is releasably coupleable with the instrument holder carriage 128.The shaft 220 extends distally from the transmission assembly 210. Theend effector 230 is disposed at a distal end of the shaft 220.

The shaft 220 defines a longitudinal axis 222 that is coincident with alongitudinal axis of the cannula 180. As the instrument holder carriage128 translates along the instrument holder frame 124, the elongate shaft220 of the surgical instrument 200 is moved along the longitudinal axis222. In such a manner, the end effector 230 can be inserted and/orretracted from a surgical workspace within the body of a patient.

Also referring to FIG. 4, another example patient-side system 160 forminimally invasive computer-assisted tele-operated surgery includes afirst robotic manipulator arm assembly 162 and a second roboticmanipulator arm assembly 164 that are each mounted to an operating table10. In some cases, this configuration of patient-side system 160 can beused as an alternative to the patient-side unit100 of FIG. 1. While onlytwo robotic manipulator arm assemblies 162 and 164 are depicted, itshould be understood that more than two (e.g., three, four, five, six,and more than six) can be included in some configurations.

In some cases, the operating table 10 may be moved or reconfiguredduring the surgery. For example, in some cases, the operating table 10may be tilted about various axes, raised, lowered, pivoted, rotated, andthe like. In some cases, by manipulating the orientation of theoperating table 10, the clinicians can utilize the effects of gravity toposition internal organs of the patient in positions that facilitateenhanced surgical access. In some cases, such movements of the operatingtable 10 may be integrated as a part of the computer-assistedtele-operated surgery system, and controlled by the system.

Also referring to FIGS. 5-7, a variety of alternative computer-assistedtele-operated surgical instruments of different types and differing endeffectors 230 may be used, with the instruments of at least some of themanipulators being removed and replaced during a surgical procedure.Several of these end effectors, including, for example, DeBakey Forceps56 i, microforceps 56 ii, and Potts scissors 56 iii include first andsecond end effector elements 56 a, 56 b which pivot relative to eachother so as to define a pair of end effector jaws. Other end effectors,including scalpels and electrocautery probes, have a single end effectorelement. For instruments having end effector jaws, the jaws will oftenbe actuated by squeezing the grip members of input devices 41, 42.

In some cases, the computer-assisted tele-operated surgical instrumentsinclude multiple degrees of freedom such as, but not limited to, roll,pitch, yaw, insertion depth, opening/closing of jaws, actuation ofstaple delivery, activation of electro-cautery, and the like. At leastsome of such degrees of freedom can be actuated by an instrument drivesystem to which the surgical instrument can be selectively coupled.

In some embodiments, the computer-assisted tele-operated surgicalinstruments include end effectors with two individually movablecomponents such as, but not limited to, opposing jaws designed forgrasping or shearing. When a first one of the individually movablecomponents is moved as a second one of the individually movablecomponents remains generally stationary or is moved in an opposingmanner, the end effector can perform useful motions such as opening andclosing for grasping, shearing, releasing, and the like. When the twocomponents are moved synchronously in the same direction, speed anddistance, the resulting motion is a type of pitch or yaw movement of theend effector. Hence, in some surgical instrument embodiments that haveend effectors with two individually movable components, such as jaws,the arrangement can provide two degrees of freedom (e.g., pitch/yawmovements and opening/closing movements).

The elongate shaft 220 allow the end effector 230 and the distal end ofthe shaft 220 to be inserted distally into a surgical worksite through aminimally invasive aperture (via cannula 180), often through a body wall(e.g., abdominal wall) or the like. In some cases, a body wall retractormember on a distal end of the cannula 180 can be used to tent the bodywall, thereby increasing the surgical workspace size. In some cases thesurgical worksite may be insufflated, and movement of the end effectors230 within the patient will often be effected, at least in part, bypivoting of the instruments 200 about the location at which the shaft220 passes through the minimally invasive aperture. In other words, therobotic manipulator arm assemblies 120, 130, 140, and 150 will move thetransmission assembly 210 outside the patient so that the shaft 220extends through a minimally invasive aperture location so as to helpprovide a desired movement of end effector 50. Hence, the roboticmanipulator arm assemblies 120, 130, 140, and 150 will often undergosignificant movement outside patient during a surgical procedure.

Referring to FIG. 8, an example surgical instrument 300 that can be usedas part of a computer-assisted tele-operated surgery system isschematically depicted. The surgical instrument 300 includes aninstrument shaft 302 (similar to shafts 220, 640) having a proximal(away from the surgical site) end portion 310 and a distal (toward thesurgical site) end portion 320 opposite from the proximal end portion310. The surgical instrument 300 also includes an end effector 330(similar to end effectors 230, 650). In this schematic diagram, the endeffector 330 is depicted as having a single degree of freedom inrelation to the instrument shaft 302 (i.e., a freedom to yaw the endeffector 330 in a rotary or pivoting fashion). It should be understood,however, that the end effectors 330 of the surgical instrumentsdescribed herein can have more than one degree of freedom (e.g., two,three, four, five, six, or more than six degrees of freedom). Moreover,it should be understood that the concepts described in the context ofthe single degree of freedom of the end effector 330 can be extended toeach degree of freedom of multiple degrees of freedom of the surgicalinstrument 300 and of other types of surgical instruments forcomputer-assisted tele-operated surgery systems.

Example surgical instrument 300 also includes a first tensioning member340, a first actuator engagement member 350, a second tensioning member360, and a second actuator engagement member 370. The first tensioningmember 340 is coupled to the end effector 330 and extends along theinstrument shaft 302 where it terminates at the first actuatorengagement member 350. Similarly, the second tensioning member 360 iscoupled to the end effector 330 and extends along the instrument shaft302 where it terminates at the second actuator engagement member 370.The first actuator engagement member 350 and the second actuatorengagement member 370 are movably coupled to the proximal end portion310 of the surgical instrument. In some embodiments, the first actuatorengagement member 350 and the second actuator engagement member 370 areslidably coupled to the proximal end portion 310 of the surgicalinstrument.

While the depicted embodiment includes sliding actuator engagementmembers 350 and 370, in some embodiments one or more other types ofactuator engagement members can be included in the surgical instrument300. For example, in some embodiments rotatable actuator engagementmembers are included. Such rotatable actuator engagement members can becoupled to capstans or pulleys that are engaged with the tensioningmembers 340 and 360. Rotation of the rotatable actuator engagementmembers can apply or relieve tension on the corresponding tensioningmember 340 and 360. Accordingly, movements of the end effector 330 andtensioning of the tensioning member 340 and 360 can be controlled viarotatable actuator engagement members.

In some embodiments, some or all portions of the first tensioning member340 and the second tensioning member 360 comprise flexible cables (e.g.,without limitation, stranded tungsten cables, stainless steel cables,etc.). In some embodiments, the first tensioning member 340 and thesecond tensioning member 360 are different portions of a singlecontinuous cable. In some embodiments, the first tensioning member 340and the second tensioning member 360 are separate cables. The firsttensioning member 340 and the second tensioning member 360 mayadditionally or alternatively include other components such as, but notlimited to, hypo-tubes.

The first tensioning member 340 and the second tensioning member 360 areeach coupled to the end effector 330. In the depicted embodiment, thefirst tensioning member 340 and the second tensioning member 360 areeach coupled to the end effector 330 via a pulley 332 (which can be acapstan, crank arm, rotary drive member, etc.). Hence, a proximalmovement of the first actuator engagement member 350 moves the secondactuator engagement member 370 distally, and moves the end effector 330in a first manner relative to the instrument shaft 302. Conversely, aproximal movement of the second actuator engagement member 370 moves thefirst actuator engagement member 350 distally, and moves the endeffector 330 in a second manner relative to the instrument shaft 302. Inthis fashion, desired movements of the end effector 330 can befacilitated in a controlled manner. Moreover, as described furtherbelow, while the movements and/or pose of the end effector 330 is beingcontrolled using actuator engagement members 350 and 370, the tensionsin the tensioning members 340 and 360 can be concurrently controlled. Ineffect, two degrees of freedom (e.g., end effector 330 position andtensioning members 340 and 360 tension) of the surgical instrument 300can be concurrently controlled in accordance with the devices andmethods described herein.

The surgical instrument 300 is depicted here as being separated from aninstrument drive system. Accordingly, in some embodiments the tension inthe first tensioning member 340 and the second tensioning member 360 canbe less than the tension used during the operation of the surgicalinstrument 300. In some cases, having a relatively low tension in thefirst tensioning member 340 and the second tensioning member 360 whilethe surgical instrument 300 is not in use can be advantageous (e.g., toreduce the potential for cable stretch). In some embodiments, pre-loadtensioning members (e.g., springs, not shown) may be included insurgical instrument 300 to maintain a minimal tension in the firsttensioning member 340 and the second tensioning member 360 while thesurgical instrument 300 is separated from an instrument drive system.Such minimal pre-tensioning may help ensure that the first tensioningmember 340 and the second tensioning member 360 remain oriented withinthe surgical instrument 300 as desired.

While the surgical instrument 300 is depicted as having a single degreeof freedom, it should be understood that this is a simplified schematicdiagram and that the surgical instrument 300 can have two or moredegrees of freedom. The concepts described herein in reference to thesingle degree of freedom of surgical instrument 300 (as depicted) can beextrapolated to the two or more degrees of freedom of the surgicalinstruments provided herein. For example, when the end effector 330includes two individually movable components, such as opposing jawsdesigned for grasping or shearing as described above, the arrangementprovides two degrees of freedom (e.g., pitch/yaw movements when thecomponents are moved synchronously and opening/closing movements whenthe components are moved asynchronously or in an opposing manner).Extending the concepts described in reference to the surgical instrument300 to such an end effector would result in an instrument having fouractuator engagement members and four tensioning members to actuate thetwo degrees of freedom.

Referring to FIG. 9, the surgical instrument 300 can be selectivelycoupled with an instrument drive system 400. That is, the surgicalinstrument 300 can be coupled with the instrument drive system 400 foroperation as part of a computer-assisted tele-operated surgery system.Additionally, the surgical instrument 300 can be uncoupled from theinstrument drive system 400 (e.g., for replacement by another type ofsurgical instrument, for sterilization of the surgical instrument 300,etc.).

In some embodiments, the instrument drive system 400 can be mounted to amanipulator assembly, which can in turn be mounted to another structureor a base. The instrument drive system 400 can be interchangeablymounted to a manipulator assembly in some cases. That is, in someembodiments the instrument drive system 400 is designed for convenientdetachment from a manipulator assembly such that it is readilyinterchangeable with another instrument drive system. Therefore, theinstrument drive system 400 may also be referred to as a pod 400. Asused herein, the term “pod” indicates the interchangeable aspects ofsome instrument drive systems in relation to a manipulatorassembly—i.e., one pod may be removed from a manipulator assembly andreplaced with a second pod of the same, similar, or differentconfiguration. In some embodiments, the instrument drive system 400 isaffixed to a manipulator assembly in such a way that the instrumentdrive system 400 is not readily detachable or interchangeable.

In some embodiments, the surgical instrument 300 is slidably coupleablewith the instrument drive system 400. That is, the surgical instrument300 can be slidably extended distally and slidably retracted proximallyin relation to the instrument drive system 400.

In the depicted embodiment, the instrument drive system 400 includes afirst actuator 410, a second actuator 420, and a shaft actuator 430. Thefirst actuator 410 is releasably coupleable with the first actuatorengagement member 350. Hence, the first actuator 410 can induce atensile force in the first tensioning member 340. The second actuator420 is releasably coupleable with the second actuator engagement member370. Hence, the second actuator 420 can induce a tensile force in thesecond tensioning member 360. The actuators 410, 420 are shown in anon-detained engagement with the corresponding actuator engagementmembers 350, 370. Optionally, the actuators 410, 420 are in a detainedengagement with the corresponding actuator engagement members 350, 370,such as a latch. In a detained engagement, two objects are fixedtogether (releasably or otherwise) so that as one object moves, theother object correspondingly moves. In a non-detained engagement, thetwo objects are not fixed together, so that if one object moves towardthe other, the other object moves, but if one object moves away from theother, the other object will not move.

In light of the arrangement between the surgical instrument 300 and thefirst and second actuators 410 and 420 of the instrument drive system400 as described above, it can be envisioned that concerted modulationof the forces exerted from the first and second actuators 410 and 420 tothe first and second actuator engagement members 350 and 370,respectively, can result in controlled motion of the end effector 330 inits degree of freedom. Moreover, it can also be envisioned (as describedfurther below), that the tensions in the first and second tensioningmembers 340 and 360 can also be controlled by the concerted modulationof the forces exerted from the first and second actuators 410 and 420 tothe first and second actuator engagement members 350 and 370,respectively. Still further, it can also be envisioned that the tensionsin the first and second tensioning members 340 and 360 can be controlledby the concerted modulation of the forces exerted from the first andsecond actuators 410 and 420 to the first and second actuator engagementmembers 350 and 370, respectively, while the concerted modulation of theforces exerted from the first and second actuators 410 and 420 to thefirst and second actuator engagement members 350 and 370 alsoconcurrently cause desired movements of the end effector 330. Put moresimply, the tensions in the first and second tensioning members 340 and360 can be controlled to a desired amount of tensile force whilemovements of the end effector 330 are being made as desired. Thisconcept can be referred to herein as “dynamic tension control” or“dynamic tension and position control.”

Still referring to FIG. 9, the instrument drive system 400 also includesthe shaft actuator 430 that engages with a corresponding shaft actuatorengagement member on the surgical instrument in a non-detained ordetained engagement. An example of non-detained engagement is engagementwith a part of distal end portion 310 that acts as the shaft actuatorengagement member, as shown. An example of detained engagement isengagement with a latch, as described below. The shaft actuator 430releasably couples with the instrument shaft 302 for both detained andnon-detained engagement.

In some embodiments, the shaft actuator 430 releasably couples with theinstrument shaft 302 (or to a structure coupled to the instrument shaft302) using a latch mechanism. Accordingly, in some such embodiments,while the shaft actuator 430 is latched to the instrument 300, the shaftactuator 430 is able to exert either a distally-directed force or aproximally-directed force to distally extend or proximally retract theinstrument 300, as desired, in relation to the instrument drive system400. It should be understood that such a latch mechanism for couplingthe shaft actuator 430 to the instrument shaft 302 is not required inall embodiments. Further, in some embodiments the shaft actuator 430 isconfigured to only exert a distally-directed force to the instrument 300(i.e., not a proximally-directed force). The dynamic tension andposition control concepts described herein can still be performed whilethe shaft actuator 430 is configured to exert only a distally-directedforce to the instrument 300.

The actuators 410, 420, and 430 can be various types of actuators. Insome embodiments, the first actuator 410, a second actuator 420, and ashaft actuator 430 each comprise electrical motors that are coupled tolead screws that linearly drive nut members on the threads of the leadscrew. In some embodiments, the entire assembly of the surgicalinstrument 300 in combination with the instrument drive system 400 canbe driven together to result in a desired motion of the end effector,such as a rolling motion about the longitudinal axis of the surgicalinstrument 300.

Referring also to FIG. 10, a force diagram 500 can be used to furtherdescribe the structure and operations of the surgical instrument 300 incombination with the instrument drive system 400. The body 301 isrepresentative of the surgical instrument 300. Force f₁ isrepresentative of the force applied by the first actuator 410 to thefirst engagement member 350. Force f₂ is representative of the forceapplied by the second actuator 420 to the second engagement member 370.Force f_(s) is representative of the force applied by the shaft actuator430 to the instrument shaft 302.

Force f_(s) is directionally opposite to forces f₁ and f₂. Hence, in astatic context, force f_(s) is equal to the sum of forces f₁ and f₂. Ina dynamic context, if force f_(s) is greater than the sum of forces f₁and f₂, then the body 301 will move in the direction of force f_(s).Conversely, if force f_(s) is less than the sum of forces f₁ and f₂,then the body 301 will move in the direction of forces f₁ and f₂.

Applying the principles described above regarding the force diagram 500to the analogous arrangement of the surgical instrument 300 incombination with the instrument drive system 400, the following conceptscan be envisioned. While the surgical instrument 300 is in a constantspatial relationship with the instrument drive system 400 (i.e., in astatic context), the sum of the forces exerted from the first and secondactuators 410 and 420 to the first and second actuator engagementmembers 350 and 370 equal the force exerted from the shaft actuator 430to the instrument shaft 302. In addition, while the sum of the forcesexerted from the first and second actuators 410 and 420 to the first andsecond actuator engagement members 350 and 370 are greater than theforce exerted from the shaft actuator 430 to the instrument shaft 302,the surgical instrument 300 will move proximally in relation to theinstrument drive system 400. Still further, while the sum of the forcesexerted from the first and second actuators 410 and 420 to the first andsecond actuator engagement members 350 and 370 are less than the forceexerted from the shaft actuator 430 to the instrument shaft 302, thesurgical instrument 300 will move distally in relation to the instrumentdrive system 400.

To be clear, the combinations of forces from the actuators 410, 420, and430 that cause the proximal and distal movements of the surgicalinstrument 300 in relation to the instrument drive system 400 involvethe sum of the forces exerted from the first and second actuators 410and 420 to the first and second actuator engagement members 350 and 370.Hence, it can be envisioned that the forces exerted from the first andsecond actuators 410 and 420 to the first and second actuator engagementmembers 350 and 370 can be equal to each other, or can differ from eachother while the sum is still a total amount that is appropriate toresult in a desired distal/proximal movement and/or orientation betweenthe surgical instrument 300 and the instrument drive system 400. Forexample, in the case when the forces exerted from the first and secondactuators 410 and 420 to the first and second actuator engagementmembers 350 and 370 differ from each other, a movement of end effector330 will result, and in the case when the forces exerted from the firstand second actuators 410 and 420 to the first and second actuatorengagement members 350 and 370 are equal to each other, the end effector330 will be stationary in relation to the instrument shaft 302. Again,it should be understood that, using the structure and operationalconcepts provided herein, distal/proximal movements of the surgicalinstrument 300 in relation to the instrument drive system 400 can bemade concurrently with movements of the end effector 300 in relation tothe instrument shaft 302. Moreover, both such movements can be madeconcurrently while the tensions in the first tensioning member 340 andthe second tensioning member 360 are maintained at a desired level oftensile force (e.g., within a target range of desired tensile force).

It should be understood that the force exerted by actuator 430 may bethe prime moving force, so that instrument 330 insertion and withdrawalis directly controlled by actuator 430, and actuators 410,420 applyforce sufficient to maintain tension in tension elements 340,360 and tomaintain or change end effector 330's orientation as actuator 430inserts and withdraws the instrument. And so, in one aspect actuator 430controls instrument 300's insertion and withdrawal location whileactuators 410,420 react to control tension on tension elements 340,360as the location changes. For example, when actuator 430 slightlyincreases force to insert the instrument shaft, the slight tensionincrease in tension elements 340,360 is sensed and so actuators 410,420decrease force to return tension elements 340,360 to the desired value.Alternatively, instrument 330 insertion and withdrawal is controlled byactuators 410,420,430 working in concert to control tension on tensionelements 340,360 which in turn controls instrument 300's insertion andwithdrawal location, and at the same time end effector 330's orientationis maintained or changed by actuators 410,420 working together tocontrol relative tension between tension elements 340,360. For example,when actuator 430 slightly increases force to insert the instrumentshaft, actuators 410,420 simultaneously decrease force to maintaintension in tension elements 340,360 at the desired value. It can beappreciated that these two tension-control aspects apply to a reversesituation in which actuators 410,420 act together to apply the primemoving force for insertion/withdrawal, with actuator 430 controllingtension in the tension members. And, it can be appreciated that thesetension-control aspects apply to more complicated movements in which theinstrument shaft is moved in insertion/withdrawal and the end effectoris moved in one or more degrees of freedom.

Referring also to FIGS. 11-13, the concepts described above can befurther described by examples using illustrations of the surgicalinstrument 300 in various positions in relation to the instrument drivesystem 400.

In a first example, the arrangement of FIG. 9 can be transitioned tothat of FIG. 11 by temporarily increasing the force exerted by the firstactuator 410 to the first actuator engagement member 350 in comparisonto the force exerted by the second actuator 420 to the second actuatorengagement member 370, while the sum of the two forces is held equal tothe force exerted by the shaft actuator 430 to the instrument shaft 302.In result, the end effector 330 will move in relation to the instrumentshaft 302 while the surgical instrument 300 is maintained in a constantspatial relationship (i.e., no distal and proximal movements) inrelation to the instrument drive 400. Such a movement can be made whilethe tensions in the first tensioning member 340 and the secondtensioning member 360 are maintained at a desired level of tensile force(e.g., within a target range of desired tensile force).

In a second example, the arrangement of FIG. 9 can be transitioned tothat of FIG. 12 by temporarily increasing the force exerted by the firstactuator 410 to the first actuator engagement member 350 in comparisonto the force exerted by the second actuator 420 to the second actuatorengagement member 370, while the sum of the two forces is temporarilyless than the force exerted by the shaft actuator 430 to the instrumentshaft 302. In result, the end effector 330 will move in relation to theinstrument shaft 302, and the surgical instrument 300 will extenddistally in relation to the instrument drive 400. Such movements can bemade while the tensions in the first tensioning member 340 and thesecond tensioning member 360 are maintained at a desired level oftensile force (e.g., within a target range of desired tensile force).

In a third example, the arrangement of FIG. 9 can be transitioned tothat of FIG. 13 by temporarily increasing the force exerted by the firstactuator 410 to the first actuator engagement member 350 in comparisonto the force exerted by the second actuator 420 to the second actuatorengagement member 370, while the sum of the two forces is temporarilygreater than the force exerted by the shaft actuator 430 to theinstrument shaft 302. In result, the end effector 330 will move inrelation to the instrument shaft 302, and the surgical instrument 300will retract proximally in relation to the instrument drive 400. Suchmovements can be made while the tensions in the first tensioning member340 and the second tensioning member 360 are maintained at a desiredlevel of tensile force (e.g., within a target range of desired tensileforce).

In a fourth example, the arrangement of FIG. 12 can be transitioned tothat of FIG. 13 by maintaining equal forces exerted by the firstactuator 410 to the first actuator engagement member 350 and by thesecond actuator 420 exerted to the second actuator engagement member370, while the sum of the two forces is temporarily greater than theforce exerted by the shaft actuator 430 to the instrument shaft 302. Inresult, the end effector 330 will not move in relation to the instrumentshaft 302, and the surgical instrument 300 will retract proximally inrelation to the instrument drive 400. Such a movement can be made whilethe tensions in the first tensioning member 340 and the secondtensioning member 360 are maintained at a desired level of tensile force(e.g., within a target range of desired tensile force).

In a fifth example, the arrangement of FIG. 13 can be transitioned tothat of FIG. 12 by maintaining equal forces exerted by the firstactuator 410 to the first actuator engagement member 350 and by thesecond actuator 420 exerted to the second actuator engagement member370, while the sum of the two forces is temporarily less than the forceexerted by the shaft actuator 430 to the instrument shaft 302. Inresult, the end effector 330 will move in relation to the instrumentshaft 302, and the surgical instrument 300 will extend distally inrelation to the instrument drive 400. Such a movement can be made whilethe tensions in the first tensioning member 340 and the secondtensioning member 360 are maintained at a desired level of tensile force(e.g., within a target range of desired tensile force).

Examples so far have illustrated the drive unit's first and secondactuators applying a proximal compressive force against theircorresponding first and second actuator engagement members, and thedrive unit's shaft actuator applying a distal compressive force againstthe instrument shaft. But, in another aspect the orientations of theseforces are reversed, so that the drive unit's first and second actuatorsapply a distal compressive force against their corresponding first andsecond actuator engagement members, and the drive unit's shaft actuatorapplies a proximal compressive force against the instrument shaft. Inthis aspect, the tensioning members may be routed over pulleys so thatdistal movement of an actuator engagement member causes tension in thecorresponding tension member and associated end effector movement. Or,the tensioning members may be replaced with compression members, such aspush rods coupled to the end effector, so that distal movement of anactuator engagement member causes compression in the correspondingcompression member and associated end effector movement.

Referring to FIG. 14, in some embodiments the forces exerted by theactuators 410, 420, and/or 430 to the surgical instrument 300 can bedetected by the use of one or more force detection devices. Theoutput(s) of such force detection devices can be used for controllingthe actuators 410, 420, and/or 430 (i.e., to control movements of thesurgical instrument 300 and/or to control tensions of the first andsecond tensioning members 340 and 360).

In a first non-limiting example, the depicted arrangement includes aload cell 510 type of force sensor disposed at or near the juncturebetween the first actuator 410 and the first actuator engagement member350. In another example, the depicted arrangement includes a load cell520 type of force sensor disposed near the connection between the firstactuator 410 and a structural member 401 of the instrument drive system400. In some embodiments, the instrument drive system 400 can be a pod(i.e., readily interchangeable in relation to mounting on a manipulatorassembly).

In some embodiments, other sensors and/or other devices can be used todetect the forces exerted by the actuators 410, 420, and/or 430 to thesurgical instrument 300. For example, in some embodiments strain gaugescan be located on the actuator engagement members, e.g., the firstactuator engagement member 350. In another embodiment, the electricalcurrent drawn by electric motors of the actuators 410, 420, and/or 430can be measured and used as an indication of the forces exerted by theactuators 410, 420, and/or 430 to the surgical instrument 300. In someembodiments, a combination of such force detection devices andtechniques can be used.

Referring to FIGS. 15-18, an example surgical instrument 600 that can beused as part of a computer-assisted tele-operated surgery systemincludes a proximal end portion 610, an instrument shaft 640, and an endeffector 650. The surgical instrument 600 is an example of a surgicalinstrument that is configured in accordance with the schematic diagrams(e.g., FIGS. 8, 9, and 11-14) described above. Hence, the surgicalinstrument 600 can function in accordance with the schematic diagramsdescribed above.

The instrument shaft 640 extends distally from the proximal end portion610. The instrument shaft 640 includes a distal end portion to which theend effector 650 is coupled. The instrument shaft 640 defines alongitudinal axis 602 of the surgical instrument 600, along which theinstrument is inserted into and withdrawn from the patient.

The end effectors (e.g., end effector 650) of the surgical instrumentsdescribed herein can be any type of surgical end effector (e.g.,graspers, cutters, cautery instruments, staplers, forceps, cameras,etc.). The end effectors (e.g., end effector 650) of the surgicalinstruments described herein can have one or multiple degrees of freedom(e.g., two, three, four, five, six, seven, eight, or more than eightdegrees of freedom). Moreover, it should be understood that the conceptsdescribed herein in the context of a single degree of freedom of the endeffectors can be extended to each degree of freedom of multiple degreesof freedom of the surgical instrument 600, and of other types ofsurgical instruments for computer-assisted tele-operated surgerysystems.

In the depicted embodiment, the proximal end portion 610 includes ahandle 612, a plurality of actuator engagement members (depicted heredisposed in a grouping 630 at a same longitudinal location along thelongitudinal axis 602), and an instrument shaft actuator engagementmember 620. The plurality of actuator engagement members 630 are movablycoupled to the proximal end portion 610. In the depicted embodiment, theplurality of actuator engagement members 630 are slidably coupled to theproximal end portion 610 such that the plurality of actuator engagementmembers 630 can translate parallel to the longitudinal axis 602. Theinstrument shaft actuator engagement member 620 is coupled to theproximal end portion 610. In the depicted embodiment, instrument shaftactuator engagement member 620 is pivotably coupled to the proximal endportion 610.

The handle 612 extends radially from the longitudinal axis 602. In thedepicted embodiment, the handle 612 is the portion of proximal endportion 610 and of the entire surgical instrument 600 that radiallyextends the farthest. The handle 612 is configured to facilitate manualgripping and manipulation of the surgical instrument 600.

In some embodiments, the handle 612 includes an indicium that identifiesthe type of the surgical instrument 600. For example, in the depictedembodiment the handle 612 includes a visible indicium that is an icon614 that depicts that the surgical instrument 600 is a grasper device.In some embodiments, the handle 612 includes a machine-readableindicium, such as an RFID chip or NFC tag that can be used to store andcommunicate information pertaining to the surgical instrument 600. Forexample, such information pertaining to the surgical instrument 600 caninclude, but is not limited to, a unique identification or serialnumber, the type of instrument, the number of times the instrument hasbeen used for one or more surgical procedures, and the like.

In some embodiments, the handle 612 optionally includes one or moremagnets that an instrument drive system can use to sense the presence ofthe surgical instrument 600 mounted in the instrument drive system.

The proximal end portion 610 includes the plurality of actuatorengagement members. As depicted the actuator engagement members aredisposed in a grouping 630 at a common longitudinal location along thelongitudinal axis 602. Optionally they may be at two or morelongitudinal locations along longitudinal axis 602 so that a firstcoupled pair of actuator engagement members is at a first longitudinallocation and a second coupled pair of actuator engagement members is ata second longitudinal location, or each actuator engagement member of acoupled pair is at a different longitudinal location. The actuatorengagement members are configured to releasably engage with actuatorswhich drive the actuator engagement members and corresponding movementsof the end effector 650 as described above in reference to FIGS. 8-14.As shown, each individual actuator engagement member slideslongitudinally in a corresponding individual longitudinal slot inproximal end portion 610. In other optional aspects, however, anindividual actuator engagement member may have a different configuration(e.g., a lever, a rotating piece such as a disk or gear, a cam surface,and the like). As shown, all individual actuator engagement membersextend radially outward slightly beyond the outer perimeter of proximalend portion 610 so that the associated actuators to not extend intoproximal end portion 610. Alternatively, one or more individual actuatorengagement members may not extend to or beyond the outer perimeter ofproximal end portion (e.g., they are positioned slightly inside proximalend portion 610) so they are less prone to damage or do not snag on anobject. In this alternative configuration, the associated actuatorsextend slightly into proximal end portion 610 to engage the instrument'sactuator engagement members. All actuator engagement members may havethe same configuration, or two or more actuator engagement memberconfigurations may be used in a single instrument, as long as theactuator engagement members comply with the principles of operationdescribed with reference to FIGS. 8-14. In the depicted embodiment thefollowing example actuator engagement members are included: 632 a, 632b, 634 a, 634 b, 636 a, 636 b, and 638. More or fewer actuatorengagement members may be included in some embodiments.

The actuator engagement members, e.g., actuator engagement members 632a, 632 b, 634 a, 634 b, 636 a, 636 b, and 638, are coupled to tensioningmembers (e.g., comprising flexible cables that can be routed over smallradius pulleys (e.g., 2-10 mm scale), semi-flexible cables that cannotbe routed over small radius pulleys, rigid hypo-tubes, pull rods, etc.)that extend along the instrument shaft 640 and that are movably coupledto the end effector 650. Hence, movements of the actuator engagementmembers result in movements of the end effector 650.

In some cases, the actuator engagement members are paired (e.g.,actuator engagement members 632 a and 632 b, actuator engagement members634 a and 634 b, and actuator engagement members 636 a and 636 b) suchthat moving one actuator engagement member of the pair proximallyresults in a corresponding distal movement of the other actuatorengagement member of the pair. For example, moving actuator engagementmember 632 a proximally results in a corresponding distal movement ofactuator engagement member 632 b, and moving actuator engagement member632 b proximally results in a corresponding distal movement of actuatorengagement member 632 a. In other words, actuator engagement memberpairs move in opposition to each other.

When the structure of the surgical instrument 600 includes actuatorengagement members (e.g., actuator engagement members 632 a, 632 b, 634a, 634 b, 636 a, 636 b, and 638) that are coupled to flexible tensioningcables, it can be envisioned that distal movements of the actuatorengagement members without a corresponding proximal movement of a pairedactuator engagement member will not move the end effector 650. Rather,the flexible tensioning cable attached to the actuator engagement memberbeing moved distally would simply become flaccid (due to the limitedcolumn strength/rigidity of a flexible tensioning cable). Hence, it canbe said that, in some embodiments, the actuator engagement members 632a, 632 b, 634 a, 634 b, 636 a, 636 b, and 638 are configured to move theend effector 650 in response to receiving a proximally-directed force,and are configured to not move the end effector 650 in response toreceiving a distally-directed force. However, in some embodiments one ormore of the actuator engagement members (e.g., the actuator engagementmember 638 which is not paired with another actuator engagement member)are configured to move the end effector 650 both ways (proximally anddistally). That is, such actuator engagement members optionally drive aflexible or semi-flexible member in a manner similar to Bowdin cableoperation, or drive a rigid member in a manner similar to push/pull rodoperation. For example, in some embodiments the actuator engagementmember 638 may be configured to operate a blade of the end effector 650or a clamp in the case that the end effector 650 includes a stapler. Inthe example of the blade, the actuator engagement member 638 worksopposite to a spring (cut under drive, spring back). In the example ofthe stapler, the actuator engagement member 638 moves distally to drivethe firing sequence, while the grip-open actuation returns the actuatorengagement member 638 proximally.

Still referring to FIGS. 15-18, in the depicted arrangement of surgicalinstrument 600, the actuator engagement members 632 a, 632 b, 634 a, 634b, 636 a, 636 b, and 638 are all positioned at the same longitudinallocation along the longitudinal axis 602 of the surgical instrument.However, during use of the surgical instrument 600, the actuatorengagement members 632 a, 632 b, 634 a, 634 b, 636 a, 636 b, and 638 aremoved to various longitudinal locations along the longitudinal axis 602of the surgical instrument. This is described further by the followingexample.

When the surgical instrument 600 is coupled with an instrument drivesystem, actuators of the instrument drive system will releasably couplewith the actuator engagement members 632 a, 632 b, 634 a, 634 b, 636 a,636 b, and 638. For example, the actuators will engage the actuatorengagement members by moving proximally until a reaction force thatindicates engagement is sensed. For paired actuator engagement members632 a and 632 b, a first actuator moves proximally until actuatorengagement member 632 a is engaged, and a second actuator movesproximally until actuator engagement member 632 b is engaged. The firstand second actuators may then adjust the longitudinal position of thecorresponding actuator engagement members 632 a and 632 b to set adesired tension in corresponding paired tension members coupled to thedistal end component so that all slack or backlash is removed from thedrive train between the actuator engagement members and thecorresponding distal end component and so that movement of the actuatorengagement members results in immediate movement of the correspondingdistal end component. That is, one or more instrument drive systemactuators engage the corresponding one or more instrument actuatorengagement members and set a dynamic preload tension (which may be inaddition to the static preload tension described below) in the one ormore instrument tension members between the one or more actuatorengagement members and the corresponding instrument distal end component(e.g., wrist or end effector component).

Then, in response to input (such as from surgeon console 40 of FIG. 2),the actuators of the instrument drive system correspondingly move someor all of the actuator engagement members (e.g., the actuator engagementmembers 632 a, 632 b, 634 a, 634 b, 636 a, and/or 636 b) proximally toinitiate desired movements of the end effector 650 or other distal endcomponent. For example, for paired actuator engagement members 632 a and632 b, a first actuator of the instrument drive system may move actuatorengagement member 632 a proximally. In concert with that proximalmovement of actuator engagement member 632 a, a second actuator of theinstrument drive system may resist distal movement of actuatorengagement member 632 b, thus keeping tension on actuator engagementmember 632 b's corresponding tension member, but still allows actuatorengagement member 632 b to move distally. The second actuator'sresistance to actuator engagement member 632 b's distal movement ismodulated to maintain a desired tension in the tensioning members thatcorrespond to the actuator engagement members 632 a and 632 b. Thisoperation is performed in accordance with the dynamic tensioningconcepts described above in reference to FIGS. 8-14.

In one aspect, the control system controls the tension in each of thepaired tension members to be equal as the tension members move thecorresponding end effector. In another aspect, however, the controlsystem controls the tension in the tension members to cause a requiredload force in the loaded tension member and to maintain a minimumtension on the non-loaded tension member.

To explain this differential force aspect by example, consider pairedactuator engagement members 632 a and 632 b. When their associated endeffector is at a neutral position (e.g., centered on the instrument'slongitudinal axis and not engaged with another object), not moving, andnot experiencing a load, the control system may cause an equal force tobe applied to actuator engagement members 632 a and 632 b. This equalforce is at or above a minimum force required to remove backlash fromthe tension member connections between the end effector and the actuatorengagement members for effective control. But, the equal force is keptlow in order to reduce friction and tension loads that result inmechanical wear.

To move the associated end effector, the control system moves theactuator engagement members 632 a and 632 b in opposite directions. Theend effector movement caused by the proximal motion of actuatorengagement member 632 a may be unresisted (e.g., the end effector movesfreely) or resisted (e.g., the end effector moves against tissue oranother part of the end effector, such as a jaw moving against anotherjaw in grip). Friction in the drive train may also cause a load thatrequires a higher force be applied to actuator engagement member 632 athan is required to keep the end effector under effective control at aneutral position. Thus, the actuator associated with actuator engagementmember 632 a must increase its force against actuator engagement member632 to either continue to move the corresponding end effector or tomaintain the corresponding end effector's force against the resistance.In this situation, however, there is no need for the actuator associatedwith the paired actuator engagement member 632 b to exert a force onactuator engagement member 632 b that is the same as the force exertedon actuator engagement member 632 a. What is required is that the forceexerted on actuator engagement member 632 b be at or above a minimumthreshold necessary to keep the associated tension member from goingslack or deviating from its path, such as by leaving a pulley.

As a further illustration, if the control system causes actuatorengagement member 632 a to receive a maximum allowable force from itsassociated drive unit actuator in order to produce a maximum force atthe corresponding end effector (e.g., to produce a maximum possible endeffector grip force), then the control system may cause actuatorengagement member 632 b to receive only a minimum force required toensure that its associated tension member does not go slack and does notdisengage from its proper routing, or to receive a force between thisminimum force and the force applied to actuator engagement member 632 a.And, although this aspect applies for maximum force applied to actuatorengagement member 632 a, it also applies when lower forces are appliedso that again the conflicting tension caused by the force againstactuator engagement member 632 b is minimized. It should be understoodthat if the end effector is then to be moved in the opposite direction,the required load force is applied against actuator engagement member632 b, and the required tension-maintaining force is applied againstactuator engagement member 632 a. It should also be understood that thisdifferential force aspect applies if compression is used to move an endeffector instead of tension, so that any unnecessary compression forceis reduced or minimized.

In some embodiments of surgical instrument 600, pre-load tensioningmembers (e.g., springs 633) may be included to maintain a minimaltension in the tensioning members while the surgical instrument 600 isseparated from an instrument drive system—a static preload tension. Suchminimal pre-tensioning may help ensure that the tensioning membersremain oriented and routed within the surgical instrument 600 asdesired. In the depicted embodiment, compression springs 633 apply aproximally-directed force to the actuator engagement members 632 a, 632b, 634 a, 634 b, 636 a, 636 b, and 638 to maintain a minimal tension inthe tensioning members while the surgical instrument 600 is separatedfrom an instrument drive system. In some embodiments, other types ofpre-load tensioning members may be used such as, but not limited to,flexures created as part of shaft 640 or proximal end portion 610,extension springs, torsion springs, leaf springs, and the like. Further,in embodiments that incorporate compression members in place oftensioning members, pre-load compression members similar to thesepre-load tensioning members may be used to eliminate mechanical backlashin the drive trains between actuator engagement members and the endeffector.

Still referring to FIGS. 15-18, proximal end portion 610 includes theinstrument shaft actuator engagement member 620. The instrument shaftactuator engagement member 620 is used for releasably coupling theproximal end portion 610 to an actuator of an instrument drive system.Since the instrument shaft 640 is rigidly coupled to the proximal endportion 610, the instrument shaft actuator engagement member 620 alsoreleasably couples the instrument shaft 640 to an actuator of aninstrument drive system. This concept of using the instrument shaftactuator engagement member 620 to couple an actuator to the proximal endportion 610 and the instrument shaft 640 was introduced above by theschematic diagrams and the descriptions thereof (e.g., by FIG. 9 whichincludes the shaft actuator 430 that can releasably couple with theinstrument shaft 302). Hence, the instrument shaft actuator engagementmember 620, when coupled with an actuator of an instrument drive system,is used for moving the entire surgical instrument 600 proximally and/ordistally in relation to the instrument drive system. In addition (asdescribed in reference to the force diagram of FIG. 10), the instrumentshaft actuator engagement member 620, when coupled with an actuator ofan instrument drive system, is used for balancing proximally directedforces applied by actuators to the actuator engagement members 632 a,632 b, 634 a, 634 b, 636 a, 636 b, and 638.

In the depicted embodiment, the actuator engagement members 632 a, 632b, 634 a, 634 b, 636 a, 636 b, and 638 are configured to receiveproximally-directed forces from the actuators of an instrument drivesystem but are not configured to receive distally-directed forces fromthe actuators of an instrument drive system. In other words, theactuator engagement members 632 a, 632 b, 634 a, 634 b, 636 a, 636 b,and 638 are not detained (not immovably coupled with; a non-detainedengagement) to the actuators of an instrument drive system. Stateddifferently, the actuator engagement members 632 a, 632 b, 634 a, 634 b,636 a, 636 b, and 638 are each configured for directly facilitating(causing) movement the end effector 650 in response to receiving aproximally-directed force from a corresponding actuator, and are eachnot configured for directly facilitating movement the end effector 650in response to receiving a distally-directed force from a correspondingactuator. In contrast, in the depicted embodiment the instrument shaftactuator engagement member 620 is configured to directly facilitatemovement of the entire surgical instrument 600 proximally in response toreceiving a proximally-directed force, and is configured to directlyfacilitate movement of the entire surgical instrument 600 distally inresponse to receiving a distally-directed force. That is the casebecause the instrument shaft actuator engagement member 620 isconfigured to be releasably detained to an actuator of an instrumentdrive system. For example, in the depicted embodiment the instrumentshaft actuator engagement member 620 is a latch mechanism that can beused to releasably detain the proximal end portion 610 and theinstrument shaft 640 to an actuator of an instrument drive system. Itshould be understood that the use of a latch mechanism for theinstrument shaft actuator engagement member 620 is not required in allembodiments, and other suitable coupling mechanisms at various locationson the instrument may be used.

Further, in some embodiments the instrument shaft actuator engagementmember 620 is configured such that the instrument drive system onlyexerts distally-directed forces to the surgical instrument 600 (i.e.,not proximally-directed forces). The dynamic tension and positioncontrol concepts described herein can still be performed in such a casewhere the instrument shaft actuator engagement member 620 is configuredto receive only a distally-directed force from the instrument drivesystem. In this aspect, distally-directed force on the instrument'sshaft actuator engagement member is balanced with proximally-directedforces on the instrument's actuator engagement members.

Referring particularly to FIG. 18, in some embodiments the surgicalinstrument 600 is configured with one or more connectors or contacts forinputting energy to the end effector 650 (e.g., energy forcauterization). For example, in some embodiments the surgical instrumentmay be configured to use monopolar RF, bi-polar RF, or another energyform. In such a case, in some embodiments the one or more connectors arelocated on a proximal area 613 of the handle 612. Such a location canallow the one or more connectors to be readily accessible for connectionwith one or more cables that supply the energy. Such a location can alsoallow the connections to be made and/or disconnected while the surgicalinstrument 600 is coupled with an instrument drive system.

Referring to FIG. 19, the surgical instrument 600 can be selectivelycoupled with a compatible instrument drive system 700 (also referred toas pod 700) that defines a longitudinal axis 702 of a space configuredto receive the surgical instrument 600. In accordance with a typicalimplementation for computer-assisted tele-operated surgery, theinstrument drive system 700 can be coupled to a manipulator assembly 800with multiple degrees of freedom. In some embodiments, the pod 700 isreadily detachable from the manipulator assembly 800 such that the pod700 can be conveniently interchanged with another pod. The manipulatorassembly 800 can be attached to a supporting structure of various types(e.g., refer to FIGS. 3 and 4). The instrument shaft 640 can slidablyextend through a cannula 740 that is optionally releasably mounted tothe manipulator assembly 800 or to the instrument drive system 700.

In the depicted embodiment, the surgical instrument 600 can bereleasably coupled with the instrument drive system 700 by moving thesurgical instrument 600 distally into an opening at the proximal end 704of the instrument drive system 700. In particular, the longitudinal axis602 of the surgical instrument 600 can first be aligned with thelongitudinal axis 702 of the instrument drive system 700. Then thesurgical instrument 600 can be slid distally in relation to theinstrument drive system 700 until the instrument shaft engagement member620 couples with the instrument drive system 700.

At least portions of the handle 612 and the instrument shaft engagementmember 620 extend farther radially than adjacent portions of theinstrument drive system 700 while the surgical instrument is coupledwith the instrument drive system, so that handle 612 protrudes out ofpod 700. Accordingly, the handle 612 and instrument shaft engagementmember 620 are accessible to the hands of a user. Such accessibility canadvantageously facilitate ready decoupling of the surgical instrument600 from the instrument drive system 700.

Although not visible, the instrument drive system 700 includes multipleactuators (schematically depicted in FIGS. 9 and 11-14) that releasablycouple with the actuator engagement members 632 a, 632 b, 634 a, 634 b,636 a, 636 b, and 638 while the surgical instrument 600 is coupled withthe instrument drive system 700. In some embodiments, the actuators arelinear actuators that include lead screws and lead screw nut members,and other suitable linear actuators (e.g., chain, belt, hydraulic,pneumatic, electromagnetic, and the like) may be used. In someembodiments, non-linear actuators such as rotary actuators, orcombinations of linear and non-linear actuators, may be used to producethe antagonistic force aspects as described. In some embodiments, one ormore force sensors are included in the instrument drive system 700 bywhich forces applied to the actuator engagement members 632 a, 632 b,634 a, 634 b, 636 a, 636 b, and/or 638 can be determined and fed back tothe processor 43 (FIG. 2).

In some embodiments, the entirety of the surgical instrument 600 coupledto the instrument drive system 700 can be rotated or rolled about thelongitudinal axes 602 and 702 as a single unit. The instrument actuatorengagement member 620, when coupled to pod 700 either via an instrumentshaft insertion/withdrawal actuator or directly to pod 700, is used tosecure the instrument shaft during roll around longitudinal axis 602 aspod 700 rotates around its longitudinal axis 702. In addition, handle612 may provide extra support against pod 700 for roll. A motor at thedistal end of pod 700, either inside pod 700 or part of manipulator 800,rotates the assembly of pod 700 and instrument 600. Thus the instrumentshaft, and the distal end effector, may be simultaneouslyinserted/withdrawn and rolled.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinvention or of what may be claimed, but rather as descriptions offeatures that may be specific to particular embodiments of particularinventions. Certain features that are described in this specification inthe context of separate embodiments can also be implemented incombination in a single embodiment. Conversely, various features thatare described in the context of a single embodiment can also beimplemented in multiple embodiments separately or in any suitablesubcombination. Moreover, although features may be described herein asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various system modulesand components in the embodiments described herein should not beunderstood as requiring such separation in all embodiments, and itshould be understood that the described program components and systemscan generally be integrated together in a single product or packagedinto multiple products.

Particular embodiments of the subject matter have been described. Otherembodiments are within the scope of the following claims. For example,the actions recited in the claims can be performed in a different orderand still achieve desirable results. As one example, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

1. (canceled)
 2. A medical system comprising: a surgical instrumentcomprising: a handle; a shaft having a proximal end portion and a distalend portion; an end effector movably coupled to the distal end portion;one or more cables coupled to the end effector and extending along theshaft between the proximal and distal end portions; and multipleactuator engagement members coupled to the one or more cables, whereinmovements of the actuator engagement members cause motions of the endeffector; and a surgical instrument drive unit operably coupled to amanipulator arm of a robotic surgery system and defining an opening anda space along a longitudinal axis of the surgical instrument drive unit,wherein the opening and the space slidably receive the shaft of thesurgical instrument as the surgical instrument is releasably coupledwith the surgical instrument drive unit, the surgical instrument driveunit comprising: multiple actuators arranged around the longitudinalaxis, each of the actuators being releasably coupled with one of theactuator engagement members while the surgical instrument is coupledwith the surgical instrument drive unit, the actuators beingcontrollable to drive the movements of the actuator engagement membersthat cause the motions of the end effector; and a shaftinsertion/withdrawal actuator releasably coupleable with the surgicalinstrument, the shaft insertion/withdrawal actuator being controllableto force the shaft of the surgical instrument to: (i) distally extendalong the longitudinal axis relative to the surgical instrument driveunit and (ii) proximally retract along the longitudinal axis relative tothe surgical instrument drive unit.
 3. The medical system of claim 2,wherein the actuator engagement members of the surgical instrument arerotary members.
 4. The medical system of claim 3, wherein the actuatorsof the instrument drive system are rotary actuators.
 5. The medicalsystem of claim 2, wherein the rotation actuator is controllable todrive the handle of the surgical instrument to roll about thelongitudinal axis of the surgical instrument drive unit.
 6. The medicalsystem of claim 2, wherein the rotation actuator is controllable todrive the actuator engagement members of the surgical instrument to rollabout the longitudinal axis of the surgical instrument drive unit. 7.The medical system of claim 2, wherein the actuator engagement membersare translatable relative to the instrument shaft.
 8. The medical systemof claim 2, wherein the actuator engagement members are translatablerelative to, and parallel to, the instrument shaft.
 9. The medicalsystem of claim 2, wherein, while the surgical instrument is coupledwith the surgical instrument drive unit, the shaft of the surgicalinstrument extends through the surgical instrument drive unit.
 10. Themedical system of claim 2, wherein the one or more cables are within theshaft.
 11. The medical system of claim 2, wherein the handle isconfigured to physically latch the surgical instrument to the surgicalinstrument drive unit.
 12. The medical system of claim 2, whereinportions of the actuators contact and releasably couple with theactuator engagement members, and wherein the portions of the actuatorstranslate relative to the longitudinal axis.
 13. The medical system ofclaim 2, further comprising one or more springs arranged to tension theone or more cables.
 14. The medical system of claim 2, wherein thesurgical instrument drive unit includes an outer housing and theactuators, shaft insertion/withdrawal actuator, and rotation actuatorare all located within the outer housing.
 15. The medical system ofclaim 2, wherein at least portion of the surgical instrument drive unitrotates about the longitudinal axis as the surgical instrument isrotated about the longitudinal axis.
 16. The medical system of claim 2,wherein the handle extends radially from the shaft of the surgicalinstrument.